FAQ - CZ38 系列

CZ381x Series

[Q0462]
・Is it possible to sense both DC and AC current?
A.
・It is possible to sense both DC and AC current.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0555]
・What is the difference between maximum primary current and linear sensing range?
A.
・Maximum primary current indicates the current value which can be flown for a long time in a current sensor and depends on the cross-sectional area of the primary conductor.
CZ-381x can be damaged when it has been used for a long time over the maximum effective current value. If current flows at a short period within msec order, such as an over current, CZ-381x will not be damaged.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0556]
・How much rms current can be flown in CZ-381x?
A.
・It is possible to flow current up to 40Arms(maximum primary current) in CZ-381x.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0557]
・Can CZ-381x detect only unipolar current? (ex. Current detection of 0 to 21A)
A.
・CZ-381x can not detect only unipolar current. In that case, please consider CZ-372x.
Click here for details
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0558]
・How much current resolution can the CZ-381x achieve?
A.
・Output noise affects the resolution of the measured current. It is possible to reduce the output noise by filter and to increase the resolution depending on the filter characteristic.

(a) 1μF bypass capacitor should be placed near by the VDD pin and VSS pin of CZ-381x.
(b) CZ-381x has the ratiometric output. By making the supply voltage of CZ-381x and the reference voltage of A/D converter common, the A/D conversion error caused by the fluctuation of supply voltage is decreased. Voltage dividers (R1 and R2) are required if the reference voltage of A/D converter is less than +5V.

ex.) If the reference voltage of A/D converter is +3.3V which is its supply voltage level, R1 = 20kΩ, R2 = 39kΩ are recommended. If the reference voltage of A/D converter is different from its supply voltage level, one more voltage divider is required.

(c) Add a low-pass filter if it is necessary.
Figure 1. External Circuits Example
Figure 1. External Circuits Example
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0559]
・How big is the primary conductor resistance temperature drift of CZ-381x?
A.
・The primary conductor resistance temperature drift of CZ-381x is shown in Figure 2.
Figure 2. CZ-381x Temperature Drift of the Primary Conductor Resistance (normalized at 25°C)
Figure 2. CZ-381x Temperature Drift of the Primary Conductor Resistance (normalized at 25°C)
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0560]
・How big is the production tolerance in primary conductor resistance?
A.
・The production tolerance in primary conductor resistance is from 0.29 to 0.41mΩ at 25°C(reference value) .
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0561]
・How big is the primary conductor inductance?
A.
・The primary conductor inductance is about 3nH  at 25°C(reference value).
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0562]
・What does the ratiometric property mean?
A.
・The CZ-381x has the ratiometric property. This means that the output of the current sensor(Sensitivity and Zero-current voltage) changes proportionally to the supply power voltage. The ratiometric property is suitable for applications where the output is converted to digital signal using an A/D converter, and you can decrease the reference error which fluctuations of the power supply voltage of the A/D converter cause.   
[Q0585] External Circuit Case 1)shows an example of the external circuit where a 5V A/D converter is connected. [Q0585] External Circuit Case 2)shows the case where a 3V A/D is used. The supply voltage of the CZ-381x and the reference voltage of A/D converter fluctuate at the same ratio. These circuit can avoid the effects of the fluctuation of the power supply, and you can use the A/D converter output without error.
Figure 3. Output voltage of the CZ-3813 vs Input Current with different VDD.
Figure 3. Output voltage of the CZ-3813 vs Input Current with different VDD.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0563]
・How fast is the power-on time ?
A.
・Figure 4. shows a recommended example of the power up sequence. In the power up sequence, if the time to VDD=5V is less than 0.4msec, the output will be stabilized after 35msec(max) from the time VDD=4.5V. If it takes 0.4msec or more, it may take longer to stabilize the output. Please check the time needed to stabilize the output in that case.
Figure 4. Recommended example of the power up sequence
Figure 4. Recommended example of the power up sequence
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0564]
・How about the frequency characteristic?
A.
・Figure 5 shows the typical frequency characteristic of the CZ-381x.
(Top : amplitude, Bottom : phase delay)
Figure 5. Frequency Response of the CZ-381x
Figure 5. Frequency Response of the CZ-381x
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0565]
・How fast is the response time?
A.
・The response time of the CZ-381x is typically 2μs with 100pF load capacitance. Figure 6 shows the pulse response waveform(N=1).
Figure 6  The CZ-381x rise response and fall response waveform
Figure 6 The CZ-381x rise response and fall response waveform
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0566]
・How fast is the recovery time from a fully saturated output?
A.
・Figure 7 shows the transient response waveform of CZ-381x(N=1). The time from saturation to normal is about 2.1μs.
Figure 7. The CZ-3803 Transient Response Waveform from the VOUT Deep Saturation. Test conditions:for saturation, IIN=50A; for linear VOUT, IIN=0A.
Figure 7. The CZ-3803 Transient Response Waveform from the VOUT Deep Saturation. Test conditions:for saturation, IIN=50A; for linear VOUT, IIN=0A.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0567]
・What happens if a load capacitance over 100pF is inserted to the CZ-381x VOUT?
A.
・CZ-381x does not output the correct value because of the oscillation of output.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0568]
・What happens if a load current over +/-2mA is applied to CZ-381x VOUT?
A.
・The CZ-381x does not output the correct value. Please use under the recommended operating conditions.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0569]
・Does CZ-381x have a magnetic hysteresis?
A.
・No, because CZ-381x does not contain any magnetic materials.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0570]
・What is the overcurrent detection function?
A.
・When the primary current exceeds overcurrent detection threshold which you can set, OCD pin outputs an overcurrent detection digital signal. (Normal output: "L", Over current detection: "H")
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0571]
・How do I use the overcurrent detection function?
A.
・Please see application note Appendix.
Click here for details
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0572]
・How fast is the response time of overcurrent detection output?
A.
・The response time of overcurrent detection output is typically 1.4μs with 50pF load capacitance.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0573]
・How is the overcurrent detection function set, when shipped?
A.
・The overcurrent detection function is set to OFF(OCD is Hi-Z) when shipped. Please see application note Appendix.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0574]
・What safety standards does the CZ-381x have?
A.
・The CZ-381x has been certified with IEC/UL-62368 and UL-1577 by the international certification association.

・IEC/UL 62368-1, 2nd Ed, 2014-12-01 (Audio/video, information and communication technology equipment Part 1: Safety requirements) (File No. E359197)
・CAN/CSA C22.2 No. 62368-1-14, 2nd Ed-(Audio/video, information and communication technology equipment Part 1: Safety requirements) (File No. E359197)
・UL1577-Optical Isolators-Edition 5.(File No. E499004)
・CSA Component Acceptance Service No. 5A-Component Acceptance Service for Optocouplers and Related Devices (File No. E499004)
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0575]
・How big is the clearance distance and the creepage distance?
A.
・The clearance distance and the creepage distance are both over 7.2mm.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0576]
・How big is the CTI value of the CZ-381x package material?
A.
・The Comparative Tracking Index (CTI) of the CZ-381x package resin is 600V. The Material Group is I.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0577]
・How big is the working voltage of the CZ-381x?
A.
・The CZ-381x can be used under the following conditions.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0578]
・Is it allowable to use this device over the rating isolation voltage in the data-sheet?
A.
・No, it cannot be used under the conditions that exceed the isolation voltage. We cannot guarantee characteristics of the CZ-381x. The device should be used under the recommended condition.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0579]
・How big is the voltage noise rejection ratio?
A.
・The voltage noise rejection ratio of the primary conductor is calculated by measuring the output while a high frequency sine wave voltage is applied as the input noise to the primary conductor.
Table 3 shows the CZ-381x series having a good voltage noise rejection ratio.
Figure 8. shows the frequency dependency of the voltage noise rejection ratio.
Table 3. Voltage Noise Rejection Ratio when high frequency sine wave voltage (20Vp-p) is applied
Table 3. Voltage Noise Rejection Ratio when high frequency sine wave voltage (20Vp-p) is applied
Figure 8. CZ-381x Noise Frequency vs Voltage Noise Rejection Ratio
Figure 8. CZ-381x Noise Frequency vs Voltage Noise Rejection Ratio
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0580]
・How do I decide the time constant value RC ?
A.
・Please decide the time constant value considering the requirement of output resolution and response time (Please refer to [Q0558]).
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0581]
・How should I solder the CZ-381x to the board?
A.
・Please refer to "Soldering condition" described in Important notices page.
Click here for details
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0582]
・Can I get the recommended land pattern?
A.
・Yes. The recommended land pattern is shown in Figure 9 & Table 4.
Figure 9. CZ-381x recommended footprint
Figure 9. CZ-381x recommended footprint
Table 4. CZ-381x recommended footprint dimensions
Table 4. CZ-381x recommended footprint dimensions
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0583]
・Can I get the board layout guidelines of CZ-381x?
A.
・Please see the application notes (2. Board Design Guidelines) here.
Click here for details
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0585]
・Can I get the recommended circuit diagram to use the CZ-381x?
A.
・In this subsection, we show three examples of the external circuit when using CZ-381x. These are just examples and there are other possible circuits. Please evaluate your external circuit by yourself.

Case1) Connecting a 5V A/D converter in the subsequent stage
(a) 1μF bypass capacitor should be placed near by the VDD pin and VSS pin of CZ-381x.
(b) Add a low-pass filter to VOUT pin if it is necessary. The RF and CF values should be fixed in consideration of the time constant.

Case2) Connecting a 3.3V A/D converter in the subsequent stage
(a) 1μF bypass capacitor should be placed near by the VDD pin and VSS pin of CZ-381x.
(b) Add a low-pass filter to VOUT pin if it is necessary. The R1 and R2 values should be fixed in consideration of the resistive divider ratio.
ex.) If the reference voltage of A/D converter is +3.3V which is its supply voltage level, R1 = 20kΩ, R2 = 39kΩ are recommended. If the reference voltage of A/D converter is different from its supply voltage level, one more voltage divider is required.
(c) Add a low-pass filter to VOUT pin if it is necessary. The RF and CF values should be fixed in consideration of the time constant.

Case3) Connecting an amplifier to change the reference voltage of the output or to change the sensitivity
(a) 1μF bypass capacitor should be placed near by the VDD pin and VSS pin of CZ-381x.
(b) R1 and R2 are resistors that decides the gain. The R0 value should be fixed in consideration of the load condition. The R1 and R2 values should be fixed in consideration of the gain.
Figure 10. External Circuit Example
Figure 10. External Circuit Example
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0586]
・Can I get the recommended condition to use CZ-381x considering less heat generation?
A.
・It is possible to flow current up to 40Arms(maximum primary current) in CZ-381x, even larger current in case of transitional. When the CZ-381x is used under conditions compliant with the safety standard, please make sure the case temperature (Tc) does not exceed 130℃ due to heat generated by primary current. Please refer to the Figure 11 for the position to measure Tc. 
If the heat dissipation is not enough, using pad on vias may help. They can suppress heat generation without increasing the trace area, by thermally connecting the primary conductors to an inner or outer thermal layer directly.
Figure 11. Position to measure package case temperature
Figure 11. Position to measure package case temperature
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0587]
・How big ESD does CZ-381x endure?
A.
・CZ-381x has the ESD tolerance which is more than 2000V at human body model (HBM) and more than 200V at machine model (MM). (Both are reference values.)
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0588]
・What should I take care of the other current lines(stray magnetic field)?
A.
・There are two Hall elements inside CZ-381x connected in a differential manner. By detecting the difference of these two Hall elements’ outputs, CZ-381x reduces the effects of stray magnetic fields as a built-in common-mode rejection function. When the same magnetic field is applied to both Hall elements, this magnetic field is deemed to be the stray and is reduced from the output of CZ-381x by the ratio of Stray Magnetic Field Reduction (Ebc: 0.01A/mT Typ.).

Example: When a stray magnetic field of 1mT is applied to the CZ-381x, the output will have additional error of 0.01A=10mA equivalent.
- CZ-3813: Sensitivity=60mV/A, Error=10mA → Output error=0.6mV
- CZ-3815: Sensitivity=33.3mV/A, Error=10mA → Output error=0.33mV

On the other hand, when different magnetic fields are applied to each Hall element, this will appear as output error. For example, a current carrying trace that runs close the CZ-381x may cause this. The extent of the error will depend on the layout of the current trace, actual current, distance from the CZ-381x, and the part number (sensitivity). Figure 13 shows some simulated examples of output error by the nearby current.
Figure 12. Examples of nearby current lines
Figure 12. Examples of nearby current lines
Figure 13. Output Error by nearby current
Figure 13. Output Error by nearby current
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0589]
・Can I get a way to estimate the temperature inside CZ-381x?
A.
・The temperature of the primary current lead frame and the sensor inside the package are almost the same, the best estimated temperature would be of the primary current lead frame.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0590]
・How much effect does CZ-381x have on the electrical characteristics with respect to temperature drift?
A.
・The graphs below show the change in characteristics when the ambient temperature is changed from -40 ° C to 125 ° C.
Figure 14 shows temperature drift of sensitivity, Figure 15 show temperature drift of zero-current output, and Figure 16 shows total accuracy.
All graphs show “Average” and “Average ±3σ” of the actual result in a certain lot.
Figure 14. Temperature Drift of Sensitivity (left), Figure 16. Temperature dependency of Total Accuracy (right)
Figure 14. Temperature Drift of Sensitivity (left), Figure 16. Temperature dependency of Total Accuracy (right)
Figure 15. Temperature Drift of Zero-current Output
Figure 15. Temperature Drift of Zero-current Output
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0591]
・What kind of impact does CZ-381x's output have, when the sudden step voltage or the sudden pulse current are applied to the primary current pins?(dV/dt, dI/dt)
A.
・Figure 17. shows the dV/dt noise property of CZ-381x output voltage (VOUT), when 1kV is applied to the primary conductor at the rise time of 1μs. The yellow line shows the input voltage waveform and the green line shows the output voltage waveform. The convergence time is as short as 4μs. Please avoid this noise by adjusting the capture timing.

Figure 18. shows the output voltage (VOUT) of CZ-381x, when a 25A pulse is applied to the primary conductor with a pulse width of 1μs. The yellow line shows the input current waveform and the green line shows the output voltage waveform. The convergence time is as short as 1μs.
Figure 17. dV/dt noise waveform (left: rise waveform, right: fall waveform)
Figure 17. dV/dt noise waveform (left: rise waveform, right: fall waveform)
Figure 18. dI/dt noise waveform
Figure 18. dI/dt noise waveform
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0592]
・Is CZ-381x halogen-free?
A.
・CZ-381x is halogen-free.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0593]
・Is CZ-381x compliant with RoHS?
A.
・CZ-381x is compliant with RoHS.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0594]
・Is CZ-381x Pb-free?
A.
・CZ-381x is Pb-free.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0595]
・What is the primary conductor made of?
A.
・The primary conductor is made of copper.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0596]
・How big is the thermal resistance of the CZ-381x?
A.
・The thermal resistance (θja) of CZ-381x is 41.7°C/W when using the board shown in Figure 19.
Table 5. Thermal Resistance measurement board
Table 5. Thermal Resistance measurement board
Figure 19. Thermal Resistance measurement board
Figure 19. Thermal Resistance measurement board
Click here for details
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0597]
・Can I use the internal EEPROM?
A.
・Yes, you can use one address.
Please see appendix section of the application note .
Click here for details
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0598]
・Is it possible to order the customized products?
A.
・It is possible to provide the customized product, depending on quantity conditions and your requirement. Please contact us.
Click here for details
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0599]
・Can I get the recommended way to use the CZ-381x?
A.
・The Zero-Current Output of the CZ-381x may drift over time within the values defined in datasheet Section 14.
Therefore, in order to minimize this drift, we recommend calibrating the Zero-Current Output by software after the power-up time of the system when the measured current is zero.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.
[Q0600]
・Can I get the recommended way to use the CZ-381x nearby the stray magnetic field components?
A.
・The CZ-381x output can be affected by devices including magnetic materials(mechanical relays, transformers, etc.)  nearby.
In the case those devices must be placed close to the CZ-381x, please check the effect on the CZ-381x current sensitivity or other characteristics. And please make sure that any bad characteristics are understood, and that your system does not have any critical effects.
Was it helpful?
Yes
No
Thank you We will reflect your opinion on the improvement of the web content.